The present invention relates to an electromagnetic filter permitting the continuous discharge of filtration products and to a filtration process using such a filter. It is more particular-y used in the reprocessing of irradiated fuels.
In such an application, a filtering unit must comply with special requirements:
firstly it must ensure an excellent clarification of the solutions resulting from dissolving the substances to be reprocessed,
it must permit a very good rinsing of the solids held back in the filter and their discharge in the form of an aqueous suspension,
it is desirable that it is able to work continuously
its structure must be such that there are no mechanical moving parts and that the pipes and passages are simple, reliable and present in small numbers,
it must have the capacity to treat solutions, whose suspensions have a high heat release, without bringing about excessive design and operating constraints, which is necessary for reprocessing solutions from fast neutron reactors.
In the past, these requirements have led to the use of two types of apparatus, namely pendulum-like centrifugal decanters and pulsed filters, the former being more widely used in existing reprocessing plants. However, in the case of the decanters, the clarification obtained is not excellent and the rinsing of the solids makes it necessary to stop the clarifying function. Moreover, they have moving mechanical parts. Finally, the construction of such equipment is difficult and it has not been shown that they can be used with highly exothermic products.
Pulsed filters are constituted by a fritted metal cartridge through which is filtered the solution to be clarified. The filtering principle is very different from that of the present invention.